Glaucoma is one of the leading causes of blindness in the United States. It produces a gradual and progressive degeneration of retinal ganglion cells, which transmit visual information along the optic nerve to the brain. Unfortunately, by the time this glaucomatous neuropathy is detected, there is typically extensive and permanent damage to the visual system and profound loss in visual function. Presently, there is a paucity of screening and diagnostic tools available to vision professionals that can aid in the early detection of this disease and in the monitoring of treatments for the purpose of neuroprotection. There is evidence to indicate that select pathways of the visual system are affected in an early stage of the disease. The long-term goals of this project are to provide vision professionals with an objective, efficient, and user-friendly instrument that will aid in the following tasks: . Detection of visual deficits as early in the disease process of glaucoma as possible . Monitoring of visual function quantitatively over time . Assessment of the efficacy of neuroprotective treatments for glaucoma The specific aims are to design a clinical electrophysiological device with the following features: 1) Stimulus presentations that drive selectively the parallel pathways known to be affected in the early stages of glaucomatous neuropathy, and that are short in duration to suit clinical usage. 2) Data analysis to extract the dominant frequency component of the responses and application of multivariate statistics to automatically reject corrupted signals, rigorously quantify the noise level in the recording and to derive an objective measure of signal-to-noise known to reveal deficits in patients with glaucoma and glaucoma suspects. 3) Windows-based graphical user interface for simplified operation by non-expert assistants.